Depletion Patterns Research Articles

Interpolation of rainfall observations during extreme rainfall events in complex mountainous terrain

AbstractThe representation of rainfall in space is important for hydrological modelling. Accurate estimation of rainfall is particularly challenging in mountainous regions where observations are often sparse relative to the spatial variability of rainfall. In these regions, orographic processes lead to complex patterns of rainfall enhancement and rain shadow depletion. This study testsNatural Neighbour Interpolation (NNI),ordinary kriging (OK)andordinary cokriging (CK), to determine ifCKimproves rainfall interpolation during three extreme rainfall events. Three different elevation indices were considered as secondary variables forCK. Preliminary analysis using long‐term annual average rainfall totals, including additional high elevation rainfall observations, showed thatCKwith an effective elevation index (a directionally smoothed elevation, corrected for degree of ‘orographic processing’ and shifted to account for ‘wind‐drift’ of rainfall) as a secondary variable performed better thanNNIandOKwith an overall improvement of around 40%. Using rainfall totals for long‐term wind direction and wind speed rainfall classes,CKperformance was variable but provided an improvement of approximately 15% for wind direction classeswithoutan easterly wind component. For 15‐min timesteps during extreme rainfall events, there were comparatively small differences (cross‐validation usingRMSE) between interpolation methods, partly attributed to having only relatively low elevation rainfall observations, providing weak constraint. Using cross‐validation andmean biasdid, however, show an improvement for both high and low elevation observation classes. Importantly, cross‐variogram estimation provided differing cross‐validation results when estimated for different rainfall accumulation periods: 15‐min, hourly, daily and long‐term. Variograms and cross variograms estimated at a 15‐min timestep frequency were robust for many timesteps, but were difficult to fit automatically for others. Variograms estimated from longer periods were more reliably estimated, but tended to have lower variance and cross‐variance and longer correlation ranges producing a smoother interpolated rainfall field. Given the weak cross‐validation constraint, care must be taken in identifying the most appropriate method and variogram estimation period.

Origin of moderately volatile element depletion on differentiated bodies: Insights from the evaporation of indium from silicate melts

In comparison with the Sun and CI chondrites, moderately volatile elements (MVEs) are depleted in terrestrial planets and other small, rocky differentiated bodies in the inner solar system. The abundances of most MVEs in the bulk silicate Earth (BSE) fall on a trend that defines a near log-linear decrease with their 50% nebular condensation temperature (Tc50). This temperature scale has traditionally been used to infer elemental volatility during planetary formation and accretion, however, indium (In) deviates from this correlation. Despite being a siderophile element that could have been depleted by core formation, In is overabundant for its calculated Tc50 in the BSE, as well as in the silicate portions of other small bodies (e.g., Moon and Vesta). This overabundance of In indicates that Tc50, calculated under nebular conditions, may not be applicable to planetary evaporation that occurs at much higher oxygen fugacity (fO2) and pressure than nominal nebular conditions. Here, we conduct a series of evaporation experiments for basaltic melts to quantify the volatility of In under conditions relevant to planetary evaporation. Our results show that, when using the evaporation temperature (Te1, refers to the temperature at which 1% of element i has evaporated from liquid to gas phase under equilibrium) as the volatility scale, the abundances of volatile elements, including In, of the Moon and Vesta display a progressive depletion with increasing volatility (decreasing Te1). This smooth depletion pattern contrasts with the overabundance of In shown on the Tc50 scale, suggesting that volatile depletion on small bodies occurred under non-nebular environment instead of during nebular condensation. On the other hand, the volatile element composition of the BSE (including In) could be explained by integrating (i) early accreted precursor materials of the proto-Earth that underwent volatile loss under conditions more oxidizing than those of the solar nebula with (ii) late added volatile-rich materials.

Association Between White Matter Networks and the Pattern of Striatal Dopamine Depletion in Patients With Parkinson Disease.

Individual variability in nigrostriatal dopaminergic denervation is an important factor underlying clinical heterogeneity in Parkinson disease (PD). This study aimed to explore whether the pattern of striatal dopamine depletion was associated with white matter (WM) networks in PD. A total of 240 newly diagnosed patients with PD who underwent 18F-FP-CIT PET scans and brain diffusion tensor imaging at initial assessment were enrolled in this study. We measured 18F-FP-CIT tracer uptake as an indirect marker for striatal dopamine depletion. Factor analysis-derived striatal dopamine loss patterns were estimated in each patient to calculate the composite scores of 4 striatal subregion factors (caudate, more-affected and less-affected sensorimotor striata, and anterior putamen) based on the availability of striatal dopamine transporter. The WM structural networks that were correlated with the composite scores of each striatal subregion factor were identified using a network-based statistical analysis. A higher composite score of caudate (i.e., relatively preserved dopaminergic innervation in the caudate) was associated with a strong structural connectivity in a single subnetwork comprising the left caudate and left frontal gyri. Selective dopamine loss in the caudate was associated with strong connectivity in the structural subnetwork whose hub nodes were bilateral thalami and left insula, which were connected to the anterior cingulum. However, no subnetworks were correlated with the composite scores of other striatal subregion factors. The connectivity strength of the network with a positive correlation with the composite score of caudate affected the frontal/executive function either directly or indirectly through the mediation of dopamine depletion in the caudate. Our findings indicate that different patterns of striatal dopamine depletion are closely associated with WM structural alterations, which may contribute to heterogeneous cognitive profiles in individuals with PD.

Different moisture regimes during the last 150 years inferred from a tree-ring δ18O network over the transitional zone of the Asian summer monsoon

The East Asian summer monsoon (EASM) and Indian summer monsoon (ISM) are two interactive climate systems dominating the moisture variability of Monsoon Asia. However, ISM-EASM interactions and their effects on regional moisture dynamics remain unclear. This study investigated the spatiotemporal characteristics of monsoon-related hydroclimate variability by establishing a new tree-ring oxygen isotope ratio (δ18Otree) network of eight δ18Otree records covering the last 150 years in southern China, which differs from previous studies that used data from individual sites. The δ18Otree chronologies were found to be sensitive to regional hydroclimatic changes during the monsoon season. The δ18Otree network indicated an east–west clustering pattern in the ISM-EASM transitional zone, which demonstrates an asynchrony in δ18Otree variability in the west and east of this region. Regional variability of the west and east δ18Otree modes reflected the different moisture signals, as indicated by their significant correlations with modern observations and paleo-δ18O records in disparate upstream regions of moisture transport (the Indochina Peninsula and Southeast China). This finding was confirmed by the east–west distinct pattern of spatial isotopic depletion of monsoon rainfall that originates from coastal areas of tropical oceans (Bay of Bengal and South China Sea) to the study area, as well as the consistent present-day pattern of atmospheric vapor transport during the monsoon season. In addition, the west and east modes exhibited stronger associations with ISM variability, whereas the east–west δ18Otree gradient captured the EASM-related hydroclimatic signal, suggesting that summer moisture variability in the ISM-EASM transitional zone was regulated more by ISM than by EASM during the last 150 years. The relationships between δ18Otree and large-scale ocean–atmosphere interaction modes revealed that the El Niño-Southern Oscillation (ENSO) dominantly modulates δ18Otree variability across southern China.

Forward and back diffusion of reactive contaminants through multi-layer low permeability sediments

Contaminants stored in the low permeability sediments will continue to threaten the adjacent shallow groundwater system after the aquifer is remediated. Understanding the storage and discharge behavior of contaminants in the aquitards is essential for the efficient remediation of contaminated sites, but most of the previous analytical studies focused on nonreactive solutes in a single homogenous aquitard. This study presents novel analytical solutions for the forward and back diffusion of contaminants through multi-layer low permeability sediments considering abiotic and biotic environmental degradation. Three representative source depletion patterns (i.e., instantaneous, linear, and exponential patterns) were selected to describe the dissolution of dense non-aqueous phase liquids (DNAPL) in the aquifer more realistically. At the forward diffusion stage, the mass storage of contaminants in the aquitards with the instantaneous pattern is the largest, nearly twice that with the exponential pattern. A simple equivalent homogeneous model is generally adopted in the risk assessment. However, relative to the proposed multi-layer model, it will significantly underestimate the onset of the back-diffusion of heterogeneous aquitards and overestimate the persistence of aquifer plumes. The previously-reported semi-infinite boundary assumption is also not applicable, with a maximum error of over 200% in the long-term prediction of back diffusion behavior of a thin aquitard. Moreover, when the degradation half-life is less than 16 years, less than 10% of the contaminants stored in the aquitards will diffuse into the overlying aquifer, suggesting that biostimulation or bioaugmentation can effectively mitigate back-diffusion risk. Overall, the proposed diffusion-reaction coupled model with multi-layer media is of great value and high demand in predicting the back-diffusion behavior of heterogeneous aquitards and guiding the soil bioremediation.

The 50th Anniversary of The Limits to Growth: Does It Have Relevance for Today’s Energy Issues?

The Limits to Growth was a remarkable, and remarkably influential, model, book and concept published 50 years ago this year. Its importance is that it used, for essentially the first time, a quantitative systems approach and a computer model to question the dominant paradigm for most of society: growth. Initially, many events, and especially the oil crisis of the 1970s, seemed to support the idea that the limits were close. Many economists argued quite the opposite, and the later relaxation of the oil crisis (and decline in gasoline prices) seemed to support the economists’ position. Many argued that the model had failed, but a careful examination of model behavior vs. global and many national data sets assessed by a number of researchers suggests that the model’s predictions (even if they had not been meant for such a specific task) were still remarkably accurate to date. While the massive changes predicted by the model have not yet come to pass globally, they are clearly occurring for many individual nations. Additionally, global patterns of climate change, fuel and mineral depletion, environmental degradation and population growth are quite as predicted by the original model. Whether or not the world as a whole continues to follow the general patterns of the model may be mostly a function of what happens with energy and whether humans can accept constraints on their propensity to keep growing.

Reduced microglia activation following metformin administration or microglia ablation is sufficient to prevent functional deficits in a mouse model of neonatal stroke

BackgroundNeonatal stroke is a devastating insult that can lead to life-long impairments. In response to hypoxic–ischaemic injury, there is loss of neurons and glia as well as a neuroinflammatory response mediated by resident immune cells, including microglia and astrocytes, which can exacerbate damage. Administration of the antidiabetic drug metformin has been shown to improve functional outcomes in preclinical models of brain injury and the cellular basis for metformin-mediated recovery is unknown. Given metformin’s demonstrated anti-inflammatory properties, we investigated its role in regulating the microglia activation and used a microglia ablation strategy to investigate the microglia-mediated outcomes in a mouse model of neonatal stroke.MethodsHypoxia-ischaemia (H-I) was performed on post-natal day 8. Metformin was administered for one week, starting one day after injury. Immunohistochemistry was used to examine the spatiotemporal response of microglia and astrocytes after hypoxia-ischaemia, with or without metformin treatment. To evaluate the effects of microglia depletion after hypoxia-ischaemia, we delivered Plexxikon 5622 for 1 or 2 weeks post-injury. The regional pattern of microglia and astrocyte depletion was assessed through immunohistochemistry. Motor behaviour was assessed with the righting reflex, hindlimb suspension, grip strength and cylinder tests.ResultsHerein, we revealed a spatiotemporally regulated response of microglia and astrocytes after hypoxia-ischaemia. Metformin treatment after hypoxia-ischaemia had no effect on microglia number and proliferation, but significantly reduced microglia activation in all regions examined, concomitant with improved behavioural outcomes in injured mice. Plexxikon 5622 treatment successfully ablated microglia, resulting in a > 90% depletion in microglia in the neonatal brain. Microglia rapidly repopulated upon treatment cessation of Plexxikon. Most interesting, microglia ablation was sufficient to reduce functional deficits after hypoxia-ischaemia, mimicking the effects of 1 week of metformin treatment post-injury.ConclusionThese results highlight the importance of regulating the neuroinflammatory response after neonatal stroke to promote recovery.

A Novel Synthetic Antibody Library with Complementarity-Determining Region Diversities Designed for an Improved Amplification Profile.

Antibody discovery by phage display consists of two phases, i.e., the binding phase and the amplification phase. Ideally, the selection process is dominated by the former, and all the retrieved clones are amplified equally during the latter. In reality, the amplification efficiency of antibody fragments varies widely among different sequences and, after a few rounds of phage display panning, the output repertoire often includes rapidly amplified sequences with low or no binding activity, significantly diminishing the efficiency of antibody isolation. In this work, a novel synthetic single-chain variable fragment (scFv) library with complementarity-determining region (CDR) diversities aimed at improved amplification efficiency was designed and constructed. A previously reported synthetic scFv library with low, non-combinatorial CDR diversities was panned against protein A superantigen, and the library repertoires before and after the panning were analyzed by next generation sequencing. The enrichment or depletion patterns of CDR sequences after panning served as the basis for the design of the new library. Especially for CDR-H3 with a higher and more random diversity, a machine learning method was applied to predict potential fast-amplified sequences among a simulated sequence repertoire. In a direct comparison with the previous generation library, the new library performed better against a panel of antigens in terms of the number of binders isolated, the number of unique sequences, and/or the speed of binder enrichment. Our results suggest that the amplification-centric design of sequence diversity is a valid strategy for the construction of highly functional phage display antibody libraries.

Inferring watershed‐scale mean snowfall magnitude and distribution using multidecadal snow reanalysis patterns and snow pillow observations

AbstractThe magnitude and spatial heterogeneity of snow are difficult to model in mountainous terrain. We investigated how historic snow patterns from a 32‐year (1985–2016) snow reanalysis, which uses the timing and rate of remotely‐sensed snow disappearance to reconstruct snow water equivalent in past years, could be used to improve current year simulations of snowfall in the Upper Tuolumne, Upper Kings, and Sagehen Creek watersheds in California's Sierra Nevada. Building on past research linking observations of fractional snow‐covered area (fSCA) to spatial patterns of snow water equivalent, fSCA maps were used to identify pairs of dates from historic years in the reanalysis with similar snow accumulation and depletion patterns. Historic snow accumulation patterns were then used to extrapolate snow accumulation observed by snow pillows to 90 m snowfall fields. These 90 m snowfall fields were used as input for snow simulations, the accuracy of which were evaluated versus airborne lidar snow depth observations. Except for water‐year 2015, which had record low snow in the Sierra Nevada and unique snow patterns, normalized snow accumulation and depletion patterns identified from historic dates with spatially correlated fSCA agreed with each other well, with mean absolute differences of approximately 10%. Domain mean winter snowfall inferred from the relationship between historic snow accumulation patterns and current year snow pillow observations had a ±13% interquartile range of biases, relative to the snow reanalysis. Finally, snow depth simulations using snow pillow observed snowfall extrapolated with historic snow accumulation patterns had 70% better coefficients of correlations, and 27% better mean absolute errors, as compared to simulations using more common snowfall forcing. This work demonstrates the benefits of repeatable snowfall patterns and satellite‐era snow reanalyses in mountainous regions with uncertain snowfall magnitude and spatial heterogeneity.

Joint inversion of muon tomography and gravity gradiometry for improved monitoring of steam‐assisted gravity drainage reservoirs

ABSTRACTSteam‐assisted gravity drainage reservoirs require an immense amount of energy and water resources, and proper monitoring of steam evolution and depletion patterns is integral to the economic and environmental efficiency of the operation. Muon tomography is a passive sensing technique, which has proven to successfully model density anomalies in a variety of applications but has not yet been applied to the oil and gas field. A previous study simulated muon intensity data to model density changes in a realistic steam‐assisted gravity drainage reservoir at 1.25 and 5 years after initial production. The results showed that muon tomography is a promising technique for monitoring steam‐assisted gravity drainage reservoirs with high spatial resolution and over short time intervals of weeks to months. Here we demonstrate the advantage of using vertical gravity gradient data and muon tomography data in a joint inversion to improve the muon‐only inverse models. Forward models for simulated muon and gravity gradient data are jointly inverted for a realistic steam‐assisted gravity drainage reservoir at 230 and 130 m total vertical depth at 1.25 years after initial production. Results show that the addition of gravity gradient data helps to constrain the density change models mainly in depth and to a smaller extent laterally. For a sparse muon sensor array of 48 sensors over a reservoir at depth, the joint inversion using gravity gradient data reduces the difference between the inverse and true model by 12% compared to a muon‐only inversion. The improvement is smaller at depth with 6%. The improvement in resolvability metrics is summarized, and limitations are discussed. The addition of multiple data types in a joint inversion improves the resulting models leading to an overall decrease in model uncertainty which can be used for improved operational efficiency in steam‐assisted gravity drainage operations.

The Gaia-ESO survey: Constraining evolutionary models and ages for young low mass stars with measurements of lithium depletion and rotation

Abstract A growing disquiet has emerged in recent years that standard stellar models are at odds with observations of the colour-magnitude diagrams (CMDs) and lithium depletion patterns of pre main sequence (PMS) stars in clusters. In this work we select 1,246 high probability K/M-type constituent members of 5 young open clusters (5–125 Myr) in the Gaia-ESO Survey to test a series of models that use standard input physics and others that incorporate surface magnetic fields or cool starspots. We find that: standard models provide systematically under-luminous isochrones for low-mass stars in the CMD and fail to predict Li-depletion of the right strength at the right colour; magnetic models provide better CMD fits with isochrones that are ∼1.5 − 2 times older, and provide better matches to Li depletion patterns. We investigate how rotation periods, most of which are determined here for the first time from Transiting Exoplanet Survey Satellite data, correlate with CMD position and Li. Among the K-stars in the older clusters we find the brightest and least Li-depleted are the fastest rotators, demonstrating the classic ‘Li-rotation connection’ for the first time at ∼35 Myr in NGC 2547, and finding some evidence that it exists in the early M-stars of NGC 2264 at <10 Myr. However, the wide dispersion in Li depletion observed in fully-convective M-dwarfs in the γ Vel cluster at ∼20 Myr appears not to be correlated with rotation and is challenging to explain without a very large (>10 Myr) age spread.

Testing a simple energy-budget model for yolk-feeding stages of cleaner fish

The use of cleaner fish is an environmentally-friendly approach to combat the salmon louse, threatening commercial salmon farming. Dynamic Energy Budget (DEB) modelling helps understand the bioenergetics of early life stages of the cleaner fish, and can thereby aid optimisation of their culturing. Here, we report on our attempts to parametrise DEBkiss models for the yolk-feeding stages of two cleaner fish species, ballan wrasse (Labrus bergylta) and lumpfish (Cyclopterus lumpus). A range of measurements was taken over early development, including biometry (using imaging), weight and composition, as well as measurements of respiration rate. Despite the previous success of applying the DEBkiss model to early life stages of Atlantic cod, the model failed to capture the patterns of yolk depletion for ballan wrasse. The main issues were related to substantial changes in the water content of both yolk and structure over development, and a stop of growth before disappearance of the yolk sac. These issues require further experimental work to address, especially more efficient proxies for the dry mass of yolk and structure, such that these compartments can be efficiently separated. Nevertheless, apart from the pattern of yolk depletion, the model provides a reasonable explanation of all traits simultaneously. This indicates that model modifications may only need to be minor. For lumpfish, the data set was quite limited for testing of the DEBkiss model, due to the opacity of the egg and the fact that there was only one time point with measurements post hatch. Nevertheless, the data are consistent with the model. The modelling results indicate that both cleaner-fish species may have very similar bioenergetic parameters (and quite similar to Atlantic cod as well); the conspicuous difference in early life history may be mainly caused by the larger yolk provisioning in the egg, and late hatching, in lumpfish. The DEBkiss model is a simple and promising tool for bioenergetics of fish early-life stages. However, its application and in-depth testing is currently limited by the difficulties of obtaining detailed measurements on these life stages.

Missense Variants Reveal Functional Insights Into the Human ARID Family of Gene Regulators

Missense variants are alterations to protein coding sequences that result in amino acid substitutions. They can be deleterious if the amino acid is required for maintaining structure or/and function, but are likely to be tolerated at other sites. Consequently, missense variation within a healthy population can mirror the effects of negative selection on protein structure and function, such that functional sites on proteins are often depleted of missense variants. Advances in high-throughput sequencing have dramatically increased the sample size of available human variation data, allowing for population-wide analysis of selective pressures. In this study, we developed a convenient set of tools, called 1D-to-3D, for visualizing the positions of missense variants on protein sequences and structures. We used these tools to characterize human homologues of the ARID family of gene regulators. ARID family members are implicated in multiple cancer types, developmental disorders, and immunological diseases but current understanding of their mechanistic roles is incomplete. Combined with phylogenetic and structural analyses, our approach allowed us to characterise sites important for protein-protein interactions, histone modification recognition, and DNA binding by the ARID proteins. We find that comparing missense depletion patterns among paralogs can reveal sub-functionalization at the level of domains. We propose that visualizing missense variants and their depletion on structures can serve as a valuable tool for complementing evolutionary and experimental findings.

Gaia-ESO Survey: Role of magnetic activity and starspots on pre-main-sequence lithium evolution

Context. It is now well-known that pre-main-sequence models with inflated radii should be taken into account to simultaneously reproduce the colour-magnitude diagram and the lithium depletion pattern observed in young open star clusters. Aims. We tested a new set of pre-main-sequence models that include radius inflation due to the presence of starspots or to magnetic inhibition of convection. We used five clusters observed by the Gaia-ESO Survey that span the age range ∼10−100 Myr, in which these effects could be important. Methods. The Gaia-ESO Survey radial velocities were combined with astrometry from Gaia EDR3 to obtain clean lists of high-probability members for the five clusters. A Bayesian maximum likelihood method was adopted to fit the observed cluster sequences to theoretical predictions to derive the best model parameters and the cluster reddening and age. Models were calculated with different values of the mixing length parameter (αML = 2.0, 1.5 and 1.0) for the cases without spots or with effective spot coverage βspot = 0.2 and 0.4. The models were also compared with the observed lithium depletion patterns. Results. To reproduce the colour-magnitude diagram and the observed lithium depletion pattern in Gamma Vel A and B and in 25 Ori, both a reduced convection efficiency, with αML = 1.0, and an effective surface spot coverage of about 20% are required. We obtained ages of 18−4.0+1.5 Myr and 21−3.0+3.5 Myr for Gamma Vel A and B, respectively, and 19−7.0+1.5 Myr for 25 Ori. However, a single isochrone is not sufficient to account for the lithium dispersion, and an increasing level of spot coverage as mass decreases seems to be required. On the other hand, the older clusters (NGC 2451 B at 30−5.0+3.0 Myr, NGC 2547 at 35−4.0+4.0 Myr, and NGC 2516 at 138−42+48 Myr) are consistent with standard models (i.e. αML = 2.0 and no spots) except at low masses: a 20% spot coverage appears to reproduce the sequence of M-type stars better and might explain the observed spread in lithium abundances. Conclusions. The quality of Gaia-ESO data combined with Gaia allows us to gain important insights on pre-main-sequence evolution. Models including starspots can provide a consistent explanation of the cluster sequences and lithium abundances observed in young clusters, although a range of starspot coverage is required to fully reproduce the data.

Fertilizer Effects on Soil Moisture Changes during Crop Growing Seasons of Dryland Agriculture in Northwestern Alberta, Canada

Efficient use of limited soil moisture resources is important for crop production in dryland agriculture in the study area. Understanding the changes in soil moisture during crop growing seasons can improve crop production. The objectives of the current study were to assess the effects of fertilizer application on soil moisture content (SMC) and its depletion patterns during the growing season. Changes in SMC in the 0-10, 10-20, 20-30, and 30-40 cm depths soil were monitored during the 2013-2015 growing seasons under canola (Brassica napus L.) and barley (Hordeum vulgare L.) crops with 0 and 100% rates of commercial chemical fertilizers. The crops were grown using direct seeding (DS) on a clay loam soil in the southeast Peace Region (legal: NW7-77-20W5; GPS: 55o39′38.43″ N, 117o6′10.64″ W) of Alberta, Canada. Fertilizer application reduced the SMC at all the soil depths during considerable crop growing seasons. Depletion of SMC started earlier in fertilized pots in 2013 and 2014, but not in the drier early season of 2015. Rapid depletion during the early and middle of growing seasons was followed by slower or no soil moisture depletion by crops near the end. The SMC tended to be somewhat lower under 100 than 0% fertilizer by the end of the growing seasons, with few exceptions. The start of SMC depletion and appearance of fertilizer rates effect after seeding was also influenced by the amount of SMC at seeding in spring, i.e. earlier in dry year of 2015 than in other years with higher SMC in spring and more rain. The results demonstrated that applying fertilizer increased soil water use by plants regardless of the crop type or growing season. They also indicated that if more soil moisture was available, the differences between fertilizer treatments might have continued for extended periods, and yields of fertilized crops may have benefitted more.

The Effects of Different Induction Regimes on Serial Lymphocyte Subsets in Kidney Transplant Recipients: A Single Tertiary Center Experience

Immunosuppressive therapy is the backbone of kidney transplantation in preventing acute rejection. T-cell depletion after doses of thymoglobulin is dose-dependent, as are their side effects. At the same time, basiliximab and other maintenance immunosuppressive drugs act at different signals on T lymphocytes. Therefore, studying the pattern of lymphocyte subset depletion depending on the induction regime given at transplantation could be an added tool in managing post-transplant recipients. This prospective observational study recruited kidney transplant recipients from August 2019 through April 2021 at the University of Malaya Medical Centre. Blood tests for lymphocyte subsets were taken at pre-transplant, 1 week, 1 month, 3 months, and 6 months post-transplantation. At transplantation, recipients received either basiliximab, low-dose thymoglobulin (cumulative dose: 1.5 mg/kg), or standard-dose thymoglobulin (cumulative dose: 5 mg/kg). A total of 39 patients were recruited: 38.5% received basiliximab (15 of 39), 15.4% received low-dose thymoglobulin (6 of 39), and 46.2% received standard-dose thymoglobulin (18 of 39). Absolute lymphocyte counts 1 week post-transplantation were 1.5 ± 0.84×109/L for basiliximab, 0.7 ± 0.57×109/L for low-dose thymoglobulin, and 0.1 ± 0.08×109/L for standard-dose thymoglobulin (P < .001). The CD4+ and CD8+ counts were severely depleted in the standard-dose thymoglobulin group, with a statistically significant differenceup to 6 months post-transplantation. In the low-dose thymoglobulin group, the CD4+ and CD8+ counts were depleted at 1 week post-transplantation and recovered at 1 month post-transplantation. There was no difference in allograft function and incidence of allograft rejection across groups. The effects on lymphocyte counts, CD4+ and CD8+, vary depending on the type and dose of induction immunosuppression. This could be a guiding tool in managing immunosuppression post-transplantation depending on the patient's immunologic risk.

INSIGHTS INTO THE ORIGIN OF SHALLOW MARINE DOLOSTONES, LONGWANGMIAO FORMATION (LOWER CAMBRIAN), NORTHEAST SICHUAN BASIN, CHINA: PETROGRAPHIC AND GEOCHEMICAL CONSTRAINTS

For a better understanding of the origin of Early Cambrian dolomites in the Sichuan Basin, which serve as valuable oil and gas reservoirs, we present and interpret complex multiparameter petrographic and geochemical analyses of dolomites in the Cambrian Longwangmiao Formation at the Yangsiqiao section. Our data show that these dolomites mainly occur in the middle and upper parts of the Longwangmiao Formation, and we identify two types of dolomites: micrite and fine-medium crystalline dolomites. The micritic dolomites, occasionally coupled with quartz and mica minerals, show dirty crystal surfaces, nonautogenous crystal shapes, and dark cathodoluminescence and mainly occur in pure micrite and granular dolostones, which retain the original sedimentary texture. Contrarily the fine-medium crystalline dolomites, mainly developed in crystalline and grain dolostones and generally coupled with residual calcites and altered sedimentary textures, have a dark heart-bright boundary texture under a polarized microscope and occasional zonal texture under cathode luminescence. Furthermore, the micritic dolomites have CaO and MgO contents approximately similar to those of the ideal stoichiometric dolomite, relatively high Sr concentration, Σ rare-earth element (REE) +Y concentrations, and δ13C and δ18O values located in the corresponding range of dolomite deposited from Early Cambrian marine water. However, light-REE enrichment (LREE), heavy-REE (HREE) depletion patterns, and high Al2O3 and SiO2 contents distinguish these micritic dolomites from typical marine carbonate deposits. Notably, the fine-medium crystalline dolomites have higher CaO content and lower MgO, Al2O3 and SiO2 contents, lower Sr and higher Fe and Mn concentrations than those of micritic dolomites. The ΣREE+Y concentrations and REE patterns of these fine-medium crystalline dolomites belong to the typical marine carbonate deposits. These features indicate considerable differences in origins between micrite and fine-medium crystalline dolomites. The micritic dolomites show a significant genetic response to the precipitation of seawater in shallow marine with the injection of terrestrial water during the syngenetic period, while the fine-medium crystalline dolomites have a typical response to the secondary metasomatism products of original calcites at the shallow burial stage.

The tragedy of the commodity is not inevitable: Indigenous resistance prevents high-value fisheries collapse in the Pacific islands

The emergence of export markets for high-value seafood products tends to produce a predictable pattern of serial depletion of resources and social disruption in coastal communities, a phenomenon described as ‘the tragedy of the commodity’. The sea cucumber trade epitomizes these challenges, with cases of rapid growth followed by fishery collapse documented across the Indo-Pacific and the majority of assessed stocks worldwide overexploited. Is this ‘boom-bust’ sequence inevitable? We examine three cases of resistance to the sea cucumber trade from Palau, Pohnpei, and Yap. Despite the overwhelming short-term financial incentives to export, fishers, youth, elected and traditional leaders, and civil society organizations coordinated to ban the trade at its peak, using public protest, court battles, and customary and statutory law. We show that, like the tragedy of the commons, Indigenous peoples and local communities can organize to resist the tragedy of the commodity. They do so by asserting Indigenous values, rights, and institutions, recommonizing the resource and preventing fisheries collapse. These cases challenge the inevitability of the tragedy of the commodity and the narrative of poor fishers as vulnerable and disempowered.

CHARACTERISTICS AND ORIGIN OF THE DOLOSTONES OF THE EDIACARAN DENGYING FORMATION IN THE EASTERN SICHUAN BASIN, SOUTH CHINA

The Ediacaran Dengying Formation dolostones were the crucial carrier of the co-evolution between the biota and environment before the Cambrian Explosion and the solid mineral and petroleum resources. Based on the petrological and mineralogical analyses, the Dengying Formation at the Liaojiacao Section consists of micritic, fine-crystalline and medium-crystalline dolostones and algal-bonded or algal-clastic dolostones. Moreover, the micritic and algal-bonded dolostones mostly retain the original sedimentary structure with widespread microbial mats, algal spots, algal traces, and other microbial fossils. Recrystallization, dissolution, and other diagenetic alterations occurred in the fine-crystalline and medium-crystalline dolostones as well as algal-clastic dolostones, and their original sedimentary structures had been significantly altered. Furthermore, in situ geochemical analysis shows that the micritic and algal-bonded dolostones of the Dengying Formation, which retain the original sedimentary structure, have Mg/Ca ratios close to the ideal primary dolomite; Na, Fe, Mn, and Sr concentrations located in the distribution range of calcites and dolomites formed in a normal marine environment, negative Ce anomaies and positive Eu anomaies with the patterns of light rare earth element depletion and medium and heavy rare earth element enrichment. In addition, the whole-rock stable isotopic analyses show that the δ13Cdol values of dolostones that retain the original sedimentary structure are consistent with the distribution range of the original marine carbonate rocks, but the δ18Odol values are slightly lower than those of the original marine carbonate rocks. Therefore, we infer that the dolostones of the Dengying Formation at the Liaojiacao Section with original sedimentary structure are the products of mimetic dolomitization and formed in an environment with extensive microbial activity, calcite as the preexisting mineral, normal salinity, and oxidized seawater as the dolomitization fluid. Moreover, the fine- and medium-crystalline dolostones were the results of recrystallization that retained the original sedimentary structures during diagenesis.

Chemical and Structural Alterations in the Amorphous Structure of Obsidian due to Nanolites.

Obsidian is volcanic glass that results from the rapid cooling of silica-rich melt. Nanoscale crystallites precipitate out of the melt prior to solidification and remain embedded in the amorphous matrix. These crystallites provide information on the flow kinetics and composition of the melt. Due to the sparsity and size of nanolites, studies often focus on supramicron crystallites. This research takes advantage of the conchoidal fracture of obsidian by knapping samples with nanometer-thin edges for transmission electron microscopy characterization. Nanolites in the amorphous matrix are studied using energy-dispersive spectroscopy (EDS) and electron diffraction. Certain alkali and alkaline-earth cations exhibit patterns of depletion near Fe-oxide nanolites. EDS is used to identify nanolites and variations in the composition of the matrix. Parallel beam diffraction and radial distribution function analysis of nearest-neighbor distances determine average bond lengths in the matrix near nanolites, showing that nanolites influence the nearby short-range ordering and atomic character of the matrix. Analysis reveals decreased mean nearest-neighbor distances in the matrix adjacent to nanolites compared to the bulk. Our methods exhibit the required sensitivity to detect variations in the composition and structure near nanolites, and our findings indicate that obsidian nanolites contribute to quantifiable localized changes in the amorphous structure.